I was modifying the named address support to add the named address keywords via
the C keyword tables rather than via a target hook, and I noticed the c_token
structure has pragma_kind as a 7 bit field. All of the previous bit fields are
8 bits in size, and next field is a tree, so we are not saving any space by
declaring the field to be 7 bits instead of 8, which would allow byte
loads/stores to be used to access the field. Here is the declaration.
typedef struct c_token GTY (())
{
/* The kind of token. */
ENUM_BITFIELD (cpp_ttype) type : 8;
/* If this token is a CPP_NAME, this value indicates whether also
declared as some kind of type. Otherwise, it is C_ID_NONE. */
ENUM_BITFIELD (c_id_kind) id_kind : 8;
/* If this token is a keyword, this value indicates which keyword.
Otherwise, this value is RID_MAX. */
ENUM_BITFIELD (rid) keyword : 8;
/* If this token is a CPP_PRAGMA, this indicates the pragma that
was seen. Otherwise it is PRAGMA_NONE. */
ENUM_BITFIELD (pragma_kind) pragma_kind : 7;
/* The value associated with this token, if any. */
tree value;
/* The location at which this token was found. */
location_t location;
} c_token;
--
Summary: c-parser.c puts pragma_kind as a 7 bit field, when 8
will generate better code
Product: gcc
Version: 4.4.0
Status: UNCONFIRMED
Severity: trivial
Priority: P3
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: gnu at the-meissners dot org
GCC build triplet: x86_64-gnu-linux
GCC host triplet: x86_64-gnu-linux
GCC target triplet: x86_64-gnu-linux
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38416
